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Sonu Sankhla - One of the best experts on this subject based on the ideXlab platform.
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temperature dependent Static Dielectric Constant and viscosity behaviour of glycerol amide binary mixtures characterization of dominant complex structures in Dielectric polarization and viscous flow processes
Journal of Molecular Liquids, 2010Co-Authors: Ram Jeewan Sengwa, Vinita Khatri, Shobhna Choudhary, Sonu SankhlaAbstract:Abstract The Static Dielectric Constant and viscosity of the binary mixtures of glycerol (Gly) with N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA) were measured over the entire composition range at temperatures 288.15, 303.15, 318.15 and 333.15 K. The concentration dependent non-linear behaviour of the measured thermodynamical parameters revealed the formation of hydrogen bond interactions between glycerol and amide molecules with a variety of complexes. The excess Dielectric Constant and excess viscosity were determined and analyzed for the confirmation of the composition of dominant complex species. Results inferred that the Dielectric polarization in both the Gly–DMF and Gly–DMA mixtures is governed by 1:1 complex species with enhanced dipolar ordering at all the investigated temperatures. The complex species of 3Gly:DMF and 2Gly:DMA facilitates the viscous flow process in Gly–DMF and Gly–DMA mixtures, respectively and the density of these species is strongly influenced by the change in temperature. Arrhenius type behaviour of viscosity against the reciprocal of temperature was used to determine the apparent activation energy of the viscous flow. The electric-field-induced increment of the Helmholtz free energy and the entropy were determined from the temperature dependence of the Static Dielectric Constant and its derivative of the binary mixtures. Results were discussed to assess the volume effect of DMF and DMA molecules on hydrogen bonding interactions with glycerol molecules in order to confirm the structural conformations of these mixed solvents.
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Temperature dependent Static Dielectric Constant and viscosity behaviour of glycerol–amide binary mixtures: Characterization of dominant complex structures in Dielectric polarization and viscous flow processes
Journal of Molecular Liquids, 2010Co-Authors: Ram Jeewan Sengwa, Vinita Khatri, Shobhna Choudhary, Sonu SankhlaAbstract:Abstract The Static Dielectric Constant and viscosity of the binary mixtures of glycerol (Gly) with N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA) were measured over the entire composition range at temperatures 288.15, 303.15, 318.15 and 333.15 K. The concentration dependent non-linear behaviour of the measured thermodynamical parameters revealed the formation of hydrogen bond interactions between glycerol and amide molecules with a variety of complexes. The excess Dielectric Constant and excess viscosity were determined and analyzed for the confirmation of the composition of dominant complex species. Results inferred that the Dielectric polarization in both the Gly–DMF and Gly–DMA mixtures is governed by 1:1 complex species with enhanced dipolar ordering at all the investigated temperatures. The complex species of 3Gly:DMF and 2Gly:DMA facilitates the viscous flow process in Gly–DMF and Gly–DMA mixtures, respectively and the density of these species is strongly influenced by the change in temperature. Arrhenius type behaviour of viscosity against the reciprocal of temperature was used to determine the apparent activation energy of the viscous flow. The electric-field-induced increment of the Helmholtz free energy and the entropy were determined from the temperature dependence of the Static Dielectric Constant and its derivative of the binary mixtures. Results were discussed to assess the volume effect of DMF and DMA molecules on hydrogen bonding interactions with glycerol molecules in order to confirm the structural conformations of these mixed solvents.
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Static Dielectric Constants and Kirkwood Correlation Factor of the Binary Mixtures of N-Methylformamide with Formamide, N,N-Dimethylformamide and N,N-Dimethylacetamide
Journal of Solution Chemistry, 2009Co-Authors: Ram Jeewan Sengwa, Vinita Khatri, Sonu SankhlaAbstract:Static Dielectric Constant values of the binary mixtures of N-methylformamide with formamide, N,N-dimethylformamide and N,N-dimethylacetamide have been measured in the whole composition range at 303 K. The Kirkwood correlation factor values of the amide–amide mixtures were determined from the measured values of the Static Dielectric Constant and high-frequency limit Dielectric Constant. The evaluated values of the excess Dielectric Constant and deviation in the Kirkwood correlation factor infer that deviations of their mixture values occur from the mole-fraction mixture law. Results confirm that there are strong hydrogen-bond interactions between unlike molecules of amide–amide mixtures and that 1:1 complexes are formed.
E. U. Franck - One of the best experts on this subject based on the ideXlab platform.
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the Static Dielectric Constant of the water benzene mixture system to 400 c and 2800 bar
Berichte der Bunsengesellschaft für physikalische Chemie, 1991Co-Authors: R. Deul, E. U. FranckAbstract:The water-benzene mixture system at high temperature and high density is considered as a model system to study the Dielectric properties of polar-nonpolar binary mixtures. The Static Dielectric Constant or permittivity e and the density have been measured at 300, 350 and 400°C between 100 and 2800 bar for 7 different water-benzene mixtures covering the whole range between pure water and pure benzene. Apparatus and procedure are described. An autoclave contains a cell closed with a flexible bellows. Inside the cell is a cylindrical condenser, filled with a sample mixture, separated from the pressurizing fluid. Thus Dielectric and density measurements can be performed simultaneously with one sample.—Extensive tables with data are given. The uncertainty is believed to be below ±1% for most data. At 400°C and 2000 bar e(χw = 1.0) is 19.40 and decreases to 9.67 (χw = 0.9) and to 3.68 (χw = 0.5). For pure benzene the value is 2.1. Several continuum theories are examined and discussed to represent the data. The best result was obtained with the Landau-Lifshitz-Looyenga relation. It needs Dielectric Constants of the pure partners and the mixture densities but requires no adjustable parameters. On the basis of the present investigation this relation is recommended also to estimate Dielectric Constants for dense, supercritical binary systems of water with nonpolar gases.
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The Static Dielectric Constant of the Water-Benzene Mixture System to 400°C and 2800 bar
Berichte der Bunsengesellschaft für physikalische Chemie, 1991Co-Authors: R. Deul, E. U. FranckAbstract:The water-benzene mixture system at high temperature and high density is considered as a model system to study the Dielectric properties of polar-nonpolar binary mixtures. The Static Dielectric Constant or permittivity e and the density have been measured at 300, 350 and 400°C between 100 and 2800 bar for 7 different water-benzene mixtures covering the whole range between pure water and pure benzene. Apparatus and procedure are described. An autoclave contains a cell closed with a flexible bellows. Inside the cell is a cylindrical condenser, filled with a sample mixture, separated from the pressurizing fluid. Thus Dielectric and density measurements can be performed simultaneously with one sample.—Extensive tables with data are given. The uncertainty is believed to be below ±1% for most data. At 400°C and 2000 bar e(χw = 1.0) is 19.40 and decreases to 9.67 (χw = 0.9) and to 3.68 (χw = 0.5). For pure benzene the value is 2.1. Several continuum theories are examined and discussed to represent the data. The best result was obtained with the Landau-Lifshitz-Looyenga relation. It needs Dielectric Constants of the pure partners and the mixture densities but requires no adjustable parameters. On the basis of the present investigation this relation is recommended also to estimate Dielectric Constants for dense, supercritical binary systems of water with nonpolar gases.
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the Static Dielectric Constant of methyl cyanide to 350 c and 2000 bar
Berichte der Bunsengesellschaft für physikalische Chemie, 1990Co-Authors: W. W. Hill, S. Rosenzweig, E. U. FranckAbstract:The relative Static Dielectric Constant e of methyl cyanide was measured from 20 to 350°C, from 50 to 2250 bar and for the liquid along the saturation line to 270°C (Tc = 274.7°C). — Equipment and experimental procedure are described. At 20°C and pressures of 50 and 2000 bar e changes from 37.7 to 42.9. At 100°C the change over the same pressure range is from 26.6 to 32.4 and at 300°C from 2.50 to 18.5. The accuracy of the data is ±0.4% up to 100°C and ±0.6% up to 300°C. Above 300°C and below 200 bar the data may be uncertain within ±1 or ±2%. Diagrams with e-values in dependence of density and temperature are given. The Kirkwood correlation factor below a density of 0.4 g cm−3 is slightly above unity. At densities higher than 0.4 g cm−3 e declines at all temperatures to about 0.8 at 0.8 g cm−3. This may indicate a certain degree of dimerization, which is discussed.
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The Static Dielectric Constant of Methyl Cyanide to 350°C and 2000 bar
Berichte der Bunsengesellschaft für physikalische Chemie, 1990Co-Authors: W. W. Hill, S. Rosenzweig, E. U. FranckAbstract:The relative Static Dielectric Constant e of methyl cyanide was measured from 20 to 350°C, from 50 to 2250 bar and for the liquid along the saturation line to 270°C (Tc = 274.7°C). — Equipment and experimental procedure are described. At 20°C and pressures of 50 and 2000 bar e changes from 37.7 to 42.9. At 100°C the change over the same pressure range is from 26.6 to 32.4 and at 300°C from 2.50 to 18.5. The accuracy of the data is ±0.4% up to 100°C and ±0.6% up to 300°C. Above 300°C and below 200 bar the data may be uncertain within ±1 or ±2%. Diagrams with e-values in dependence of density and temperature are given. The Kirkwood correlation factor below a density of 0.4 g cm−3 is slightly above unity. At densities higher than 0.4 g cm−3 e declines at all temperatures to about 0.8 at 0.8 g cm−3. This may indicate a certain degree of dimerization, which is discussed.
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The Static Dielectric Constant and density of t-butyl chloride to 200°C and 2000 bar
Berichte der Bunsengesellschaft für physikalische Chemie, 1990Co-Authors: V. C. Vani, Th. Michelberger, E. U. FranckAbstract:The relative Static Dielectric Constant or permittivity ϱ and density ρ of t-butyl chloride was measured between 25°C and 200°C and from 100 to 2000 bar. The high pressure cell, simultaneously applicable to determine e and ϱ, is described. Sample densities range from 0.694 to 0.949 g · cm−3. At 25°C and from 100 to 600 bar e increases from 9.86 to 10.59. At 100°C between 100 and 2000 bar e ranges from 6.75 to 8.57. At 200°C from 200 to 2000 bar e grows from 4.12 to 5.69. Functions for e and ρ in dependence of pressure with fitted parameters are given. Calculated Kirkwood correlation factors g are presented, which exceed unity only moderately (from 1.03 to 1.22). A comparison is made with e-values of high pressure HCl and CH3Cl.
Zhan Hong Cen - One of the best experts on this subject based on the ideXlab platform.
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Static Dielectric Constant of al nanocrystal al2o3 nanocomposite thin films determined by the capacitance voltage reconstruction technique
Applied Physics Letters, 2010Co-Authors: Zhuhong Liu, T. P. Chen, Yunya Liu, Ming Yang, Jen It Wong, Zhan Hong CenAbstract:Al nanocrystal (nc-Al)/Al2O3 nanocomposite thin films were synthesized by radio-frequency magnetron sputtering. The Static Dielectric Constant (er) of the nanocomposite thin films was determined by the capacitance-voltage reconstruction technique which was able to correct for the influence of high current conduction in the thin films. In contrast to pure Al2O3, the nanocomposite has a much higher er and its er exhibits strong temperature dependence also. The higher er is attributed to the dipole effect of the Al–O dangling bonds due to the presence of nc-Al in the Al2O3 matrix. However, the dipole effect degrades at a higher temperature, which explains the observed decrease in er with increasing temperature.
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Static Dielectric Constant of Al nanocrystal/Al2O3 nanocomposite thin films determined by the capacitance-voltage reconstruction technique
Applied Physics Letters, 2010Co-Authors: Zhuhong Liu, Tupei Chen, Yunya Liu, Ming Yang, Jen It Wong, Zhan Hong CenAbstract:Al nanocrystal (nc-Al)/Al2O3 nanocomposite thin films were synthesized by radio-frequency magnetron sputtering. The Static Dielectric Constant (er) of the nanocomposite thin films was determined by the capacitance-voltage reconstruction technique which was able to correct for the influence of high current conduction in the thin films. In contrast to pure Al2O3, the nanocomposite has a much higher er and its er exhibits strong temperature dependence also. The higher er is attributed to the dipole effect of the Al–O dangling bonds due to the presence of nc-Al in the Al2O3 matrix. However, the dipole effect degrades at a higher temperature, which explains the observed decrease in er with increasing temperature.
C.g. Joslin - One of the best experts on this subject based on the ideXlab platform.
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calculation of the Static Dielectric Constant of multipolar mixtures by perturbation theory an application to supercritical water benzene mixtures
Berichte der Bunsengesellschaft für physikalische Chemie, 1995Co-Authors: Saul Goldman, C.g. JoslinAbstract:Second-order perturbation theory for the molecular pair correlation function, together with a y-expansion of the Static Dielectric Constant (ϵ) is used to predict and interpret ϵ for supercritical benzene-water mixtures. Our predictions are compared directly with experimental results. We find that this approach, which was previously found successful provided y<3 for neat multipolar fluids, is also successful here in predicting the excess mixture Dielectric Constant, λϵ. The results are quantitative to semi-quantitative in accuracy depending slightly on the model chosen and the composition of the mixture. No adjustable parameters were used. We interpret our results in terms of underlying molecular clusters, and make a comparison with the predictions of another (non-molecular) theory.
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Calculation of the Static Dielectric Constant of Multipolar Mixtures by Perturbation Theory. An Application to Supercritical Water‐Benzene Mixtures
Berichte der Bunsengesellschaft für physikalische Chemie, 1995Co-Authors: Saul Goldman, C.g. JoslinAbstract:Second-order perturbation theory for the molecular pair correlation function, together with a y-expansion of the Static Dielectric Constant (ϵ) is used to predict and interpret ϵ for supercritical benzene-water mixtures. Our predictions are compared directly with experimental results. We find that this approach, which was previously found successful provided y
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The Static Dielectric Constant of SPC and TIP4P water by perturbation theory
The Journal of Chemical Physics, 1993Co-Authors: Saul Goldman, C.g. JoslinAbstract:A second‐order perturbation theory that was previously applied to hard‐sphere‐dipolar and Stockmayer fluids is extended to molecules with spherical cores and discrete point charge distribution of arbitrary symmetry. We use a recently published improvement on the Kirkwood superposition approximation for the reference state triplet distribution function, and we apply the theory to obtain the Static Dielectric Constant (e) of SPC and TIP4P water at ∼1 gm cm−3 and a range of temperatures. By comparison with the results of simulations on these models we find that the theory works up to y≂3 (where y is the dipolar strength function) but overestimates e beyond y≂3. y≲3 is also the range of validity of the theory when applied to a Stockmayer fluid, but for the latter the theory underestimates e for y≳3. We physically interpret our results for the angular correlation parameter (G) by reference to structures that are believed to be important in real water and in dense dipolar fluids.
Ram Jeewan Sengwa - One of the best experts on this subject based on the ideXlab platform.
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temperature dependent Static Dielectric Constant and viscosity behaviour of glycerol amide binary mixtures characterization of dominant complex structures in Dielectric polarization and viscous flow processes
Journal of Molecular Liquids, 2010Co-Authors: Ram Jeewan Sengwa, Vinita Khatri, Shobhna Choudhary, Sonu SankhlaAbstract:Abstract The Static Dielectric Constant and viscosity of the binary mixtures of glycerol (Gly) with N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA) were measured over the entire composition range at temperatures 288.15, 303.15, 318.15 and 333.15 K. The concentration dependent non-linear behaviour of the measured thermodynamical parameters revealed the formation of hydrogen bond interactions between glycerol and amide molecules with a variety of complexes. The excess Dielectric Constant and excess viscosity were determined and analyzed for the confirmation of the composition of dominant complex species. Results inferred that the Dielectric polarization in both the Gly–DMF and Gly–DMA mixtures is governed by 1:1 complex species with enhanced dipolar ordering at all the investigated temperatures. The complex species of 3Gly:DMF and 2Gly:DMA facilitates the viscous flow process in Gly–DMF and Gly–DMA mixtures, respectively and the density of these species is strongly influenced by the change in temperature. Arrhenius type behaviour of viscosity against the reciprocal of temperature was used to determine the apparent activation energy of the viscous flow. The electric-field-induced increment of the Helmholtz free energy and the entropy were determined from the temperature dependence of the Static Dielectric Constant and its derivative of the binary mixtures. Results were discussed to assess the volume effect of DMF and DMA molecules on hydrogen bonding interactions with glycerol molecules in order to confirm the structural conformations of these mixed solvents.
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Temperature dependent Static Dielectric Constant and viscosity behaviour of glycerol–amide binary mixtures: Characterization of dominant complex structures in Dielectric polarization and viscous flow processes
Journal of Molecular Liquids, 2010Co-Authors: Ram Jeewan Sengwa, Vinita Khatri, Shobhna Choudhary, Sonu SankhlaAbstract:Abstract The Static Dielectric Constant and viscosity of the binary mixtures of glycerol (Gly) with N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA) were measured over the entire composition range at temperatures 288.15, 303.15, 318.15 and 333.15 K. The concentration dependent non-linear behaviour of the measured thermodynamical parameters revealed the formation of hydrogen bond interactions between glycerol and amide molecules with a variety of complexes. The excess Dielectric Constant and excess viscosity were determined and analyzed for the confirmation of the composition of dominant complex species. Results inferred that the Dielectric polarization in both the Gly–DMF and Gly–DMA mixtures is governed by 1:1 complex species with enhanced dipolar ordering at all the investigated temperatures. The complex species of 3Gly:DMF and 2Gly:DMA facilitates the viscous flow process in Gly–DMF and Gly–DMA mixtures, respectively and the density of these species is strongly influenced by the change in temperature. Arrhenius type behaviour of viscosity against the reciprocal of temperature was used to determine the apparent activation energy of the viscous flow. The electric-field-induced increment of the Helmholtz free energy and the entropy were determined from the temperature dependence of the Static Dielectric Constant and its derivative of the binary mixtures. Results were discussed to assess the volume effect of DMF and DMA molecules on hydrogen bonding interactions with glycerol molecules in order to confirm the structural conformations of these mixed solvents.
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Static Dielectric Constants and Kirkwood Correlation Factor of the Binary Mixtures of N-Methylformamide with Formamide, N,N-Dimethylformamide and N,N-Dimethylacetamide
Journal of Solution Chemistry, 2009Co-Authors: Ram Jeewan Sengwa, Vinita Khatri, Sonu SankhlaAbstract:Static Dielectric Constant values of the binary mixtures of N-methylformamide with formamide, N,N-dimethylformamide and N,N-dimethylacetamide have been measured in the whole composition range at 303 K. The Kirkwood correlation factor values of the amide–amide mixtures were determined from the measured values of the Static Dielectric Constant and high-frequency limit Dielectric Constant. The evaluated values of the excess Dielectric Constant and deviation in the Kirkwood correlation factor infer that deviations of their mixture values occur from the mole-fraction mixture law. Results confirm that there are strong hydrogen-bond interactions between unlike molecules of amide–amide mixtures and that 1:1 complexes are formed.